The invention relates to an apparatus, connectable to a driving machine or a crane with an articulated boom system, which generates impact energy, and a method to drive into or draw up from the ground piles or similar objects.
Previously known are percussive pile drivers, connectable to cranes and driving machine, which generate the percussion and transmit it to the pile end. Especially, on driving special piles, such as wall constructions and, particularly, if they are also drawn up from the ground, the apparatus must be furnished with firm gripping jaws in order to grab the pile end and draw up the piles. Likewise, the gripping jaws are useful for lifting the piles into their place. Further, the rotative function of jaws in pile drivers are also known, by means of which plate formed profiles can be turned with the apparatus to a wanted position before starting to drive them into the ground. Also known is the turning of a vertical pile driver to horizontal position in order to grab a horizontal pile with the gripping jaws and lift it up to vertical position.
The disadvantage of the above presented drivers is the fact that they only can grip the pile end and transmit the percussions this way to the pile. Especially, when the apparatus is connected to a machine, e.g. an excavator, fitted with a boom system, very long piles cannot be handled, because the upward reach of the boom system sets limits on the pile that is being handled. The known solutions allow, indeed, gripping the pile from the side, but they do not allow driving with this grip, because the pile driver and the jaws in the known constructions are of one and the same element and therefore the percussions would drive the pile crosswise and not in the pile direction.
According to the solution of this invention these disadvantages are avoided and the invention is characterized in what is presented in the patent claims.
It can be considered the most important advantage of this invention that with the apparatus quite long piles or wall profiles can be driven into or drawn up from the ground without any limitations by the upward reach of the excavator. Further, the side grip allows also driving piles, the upper end of which is by construction or for some other reason of such kind that the percussion cannot be transmitted over it to the pile. After a short predriving and using two gripping elements arranged at a distance from each other, the driver and a part of the excavator boom system can be utilized for control of the object that is to be driven into the ground. Thereby, one or several excavator cylinders are shifted into a xe2x80x9cfloatingxe2x80x9d state by opening the valve system, where the pressure fluids on different sides of the piston can freely or almost freely flow into the cylinder or out from there. Thereby, the excavator operator avoids the difficult control of the pile driver with the boom system. The pile that is being handled can then by itself sustain its course and thereby no faulty motions or directions are transmitted to the driver.